Organism and its Environment Questions in English

(C) Statement $I$ is correct because a habitat is a physical place where an organism lives,and it can contain many different niches.
Statement $II$ is incorrect because a niche refers to the functional role and position of an organism in its environment,including its interactions with biotic and abiotic factors,not just the physical area where it lives. The definition provided in Statement $II$ actually describes a 'habitat'.

(C) Organisms that cannot maintain a constant internal body temperature and whose body temperature changes with the ambient temperature are known as $conformers$.
Approximately $99\%$ of animals and nearly all plants are conformers.
They are unable to maintain homeostasis through physiological means,so their internal environment fluctuates with the external environmental conditions.

(B) habitat is defined as the physical place or environment where an organism lives.
$1$. It is a physical space where an organism resides.
$2$. It is affected by abiotic factors like temperature,rainfall,and light.
$3$. $A$ single habitat can support numerous niches,as different species occupy different functional roles within the same physical space.
$4$. However,a habitat is $NOT$ species-specific; many different species can share the same habitat. In contrast,a 'niche' is species-specific,as it describes the functional role and requirements of a particular species.

(B) The correct matches are as follows:
$i$. Habitat niche: It refers to the physical space occupied by an organism in its environment $(i-c)$.
$ii$. Trophic niche: It refers to the functional role or the level of an organism in the food chain $(ii-d)$.
$iii$. Multidimensional niche: It refers to the position of an organism in the environmental gradient,considering multiple factors $(iii-b)$.
$iv$. Fundamental niche: It is the entire set of conditions under which an animal (population,species) can survive and reproduce itself in the absence of competition $(iv-a)$.
Therefore,the correct matching is $i-c, ii-d, iii-b, iv-a$.

(B) Statement $i$ is correct: $A$ niche describes the functional role and position of an organism in its environment.
Statement $ii$ is correct: Niche includes the energy flow and nutrient cycling associated with the organism.
Statement $iii$ is correct: If a niche becomes vacant,other organisms often adapt to fill that ecological role.
Statement $iv$ is incorrect: According to Gause's Competitive Exclusion Principle,no two species can occupy the same niche indefinitely in the same habitat.
Statement $v$ is correct: Organisms in the same habitat often have different niches to avoid direct competition.
Therefore,statements $i, ii, iii,$ and $v$ are correct.

(D) The correct matches are as follows:
$i$. Thick cuticle on leaf surface is an adaptation found in many desert plants to reduce transpiration.
$ii$. Leaves reduced to spines is a characteristic adaptation of $Opuntia$ (a desert plant) to minimize water loss.
$iii$. Desert lizards show behavioral adaptations like burrowing into sand to escape the intense heat of the desert.
$iv$. Archaebacteria are extremophiles that can survive in harsh conditions,such as hot springs.
Matching these:
$i-c$ (Thick cuticle - Desert plants)
$ii-d$ (Leaves reduced to spines - Opuntia)
$iii-a$ (Burrow into sand - Desert lizards)
$iv-b$ (Hot springs - Archaebacteria)
Therefore,the correct sequence is $i-c, ii-d, iii-a, iv-b$.

(C) By analyzing the provided graph of biome distribution:
$1$. Option $A$: The tropical forest region extends up to $450 \ cm$ of rainfall,which is the highest among all biomes shown. This statement is correct.
$2$. Option $B$: The arctic and alpine tundra region lies below the $0^{\circ}C$ mark on the y-axis. This statement is correct.
$3$. Option $C$: The tropical forest has higher rainfall than the temperate forest,but its mean annual temperature (ranging from $20^{\circ}C$ to $25^{\circ}C$) is higher than that of the temperate forest (ranging from $5^{\circ}C$ to $20^{\circ}C$). Therefore,the claim that its temperature is less than the temperate forest is incorrect.
$4$. Option $D$: The desert region is located at lower precipitation levels (mostly below $50 \ cm$) compared to the grassland region. This statement is correct.
Thus,the incorrect statement is $C$.

(B) Conformers are organisms that cannot maintain a constant internal environment. Their body temperature or osmotic concentration changes in accordance with the ambient conditions of the surrounding environment. Unlike regulators,they do not possess the physiological mechanisms to maintain homeostasis during stressful conditions.

(C) When organisms face temporary stressful environmental conditions,such as extreme cold during winter,they move away from their habitat to a more hospitable area to survive. This phenomenon is known as migration. After the stressful period ends,they return to their original habitat.

(C) The process by which organisms maintain a relatively constant internal environment despite changes in the external environment is known as $Homeostasis$.
This mechanism allows organisms to function optimally by regulating factors such as body temperature,osmotic concentration,and pH levels.
$Dormancy$ refers to a period of suspended development or metabolic activity.
$Allen's rule$ relates to the body shape of mammals in colder climates.
$Environmental gradient$ refers to the gradual change in abiotic factors over a distance.

(C) The ecological hierarchy represents the levels of biological organization in an ecosystem.
$1$. The hierarchy starts with the individual organism,which is the basic unit of ecology.
$2$. $A$ group of individuals of the same species living in a specific area forms a population.
$3$. Different populations interacting in an area form a community.
$4$. Communities along with their abiotic environment form an ecosystem.
$5$. Large regional units characterized by specific climate and vegetation are known as biomes.
Therefore,the individual organism is the fundamental unit of the ecological hierarchy.

(D) The major biomes of the world are characterized by distinct climate patterns,vegetation,and animal life.
These include:
$1$. Tundra
$2$. Desert
$3$. Tropical rain forest
$4$. Temperate forest
$5$. Coniferous forest
$6$. Grassland
Since all the options listed (Tundra,desert,tropical rain forest,temperate forest,coniferous forest,and grassland) are recognized as major biomes,the correct answer is $D$.

(D) niche describes the functional role and position of an organism in its environment.
Specifically,the physical space or the habitat occupied by an organism is referred to as its $Spatial$ niche.
Other types of niches include the $Trophic$ niche (based on feeding habits) and the $Multidimensional$ or $Hypervolume$ niche (which considers all environmental factors and resources).

(D) Thousands of migratory birds from the extremely cold regions of Siberia and the North Pole migrate to $Keoladeo$ $National$ $Park$ (formerly known as $Bharatpur$ $Bird$ $Sanctuary$) in $Rajasthan$,$India$,to escape the harsh winter conditions. This park provides a suitable habitat and food resources for these birds during the winter season.